Reasons for Demagnetization of Electrical Current Transformer

When the current suddenly decreases, the transformer core is likely to cause magnetic losses. For example, under high current conditions, the Electrical Current Transformer suddenly cuts off the power transformer, and the secondary winding resistance suddenly leads. The Electrical Current Transformer coil of this product has magnetic loss, which reduces the magnetic permeability of the transformer coil and affects the characteristics of the Electrical Current Transformer. Electrical Current Transformer used for a long time should be demagnetized. Demagnetization treatment should be carried out before inspection. Demagnetization is to alternately change the current of the excitation regulator according to the winding resistance of the primary coil or the secondary coil, so that the transformer core generates an alternating magnetic field. Starting from 0, slowly increase the alternating magnetic field (excitation regulator current) to saturate the transformer coil, then slowly reduce the excitation regulator current to zero to remove magnetic losses.

Electrical Current Transformer is demagnetized. The primary and intermediate winding resistances guide the direction, and the secondary winding resistances generate DC current. Starting from zero, the winding resistance gradually increases to a certain current value (this value is related to the precise measurement limit designed by the Electrical Current Transformer scheme, generally around 20-50% of the rated current). It can be said that if the current suddenly increases sharply, the transformer core has entered the stage of magnetic saturation. Then reduce the current to zero and do this two or three times.

Before disconnecting the power transformer, please go around the primary air before disconnecting the power supply. Demagnetize the transformer core. This method is called directional demagnetization. For some Electrical Current Transformers, many turns are generated due to the resistance of the secondary winding. If the guide demagnetization method is selected, the winding resistance in the guide direction is likely to cause excessive operating voltage. Then in the second winding resistance to a very good close connection large resistance (10-20 times the characteristic impedance of the rated current).

The color gradually changes from zero to the maximum current allowed by the initial winding resistance of the Electrical Current Transformer, and then gradually changes to zero, and so on 2-3 times. Complete demagnetization may not be possible due to the presence of coils in the load transformer. Because there is a very large current limit in the primary winding, if it is too large, there is a risk of damaging the primary winding. In the case that the standard operating voltage is not too high, the secondary winding of the input resistance can be amplified. Thus, the specific demagnetization effect is improved.